The present invention relates to a chemical reagent vial and, more specifically, a vial provided for holding metered amounts of chemical reagents having a high purity or a well defined strength, to be used for carrying out chemical reactions and/or titrations after dilution to a preset concentration.
As is known, in order to carry out a lot of chemical reactions, e.g. in chemical laboratories, reagents must be used having an accurately controlled concentration or strength: many reagents are classified as toxic and/or corrosive (i.e. sulphuric acid) and must be held in tightly closed vessels adapted to prevent the reagent from leaking and to preserve it unaltered in the time.
For laboratory use, is also known to hold accurately metered high purity or well defined titre reagent amounts within vials made of unbreakable materials (usually a plastic material) which vials or tubes have an elongated shape and two opposite open ends which are tightly closed by two frangible or pierceable elements or membranes, heat sealed on the two openings. In order to use the reagent, the vial is arranged above the mouth of a vessel or flask, and then the two above mentioned pierceable membranes are perforated or broken by a long and thin glass or stainless steel rod: then, by means of a small funnel engaged in one of the openings of the vial, a precisely metered water amount is poured into the vial (this water exiting the other opening of the vial so as to wash it and fall into the flask) in order to dilute the reagent to the titre suitable for the provided reagent use. These vials have a very simple construction, but, as the reagents have a toxic or corrosive nature, the handling and use thereof can involve hazards.
In order to overcome the above problem, vials have been designed, and also provided with an elongated shape, and hollow lugs projecting at the two open ends of each vial, where there are arranged the membranes for closing said openings: on one of said lugs (the upward turned lug) there is assembled a small funnel having a projecting tip which is brought into contact with the adjoining membrane so as to break or perforate the latter as the reagent must be used. After having poured the reagent into the flask, the funnel is properly engaged on the related lug and, through said funnel a desired diluting water amount can be poured into the vial and accordingly into the flask.
This construction, however, has the drawback that the tip projecting from the funnel greatly obstructs the diluting water flow being poured into the funnel, and that the funnel must be turned upside down after having perforated the membrane.
On the other lug (that is the lug which in use is downward turned) of the vial there is screw engaged a perforated cap, therefrom an element projects the free end whereof is made rigid with the membrane heat sealed on the end portion of said lug: as the cap is turned in the disengaging direction from its lug, said element pulls the membrane so as to tear it and allow the reagent to be ejected through the holes of the cap (after having broken, as it should be apparent, the bottom membrane of the vial). As it should be apparent, this construction is complex and difficult to make.